What happened
During a takeoff attempt at Bacchus Marsh, a Cessna 150, registration VH-EYU, encountered unstable flight conditions. After an initial rejected takeoff for unknown reasons, the pilot proceeded with a second takeoff attempt. CCTV footage indicated the aircraft's groundspeed was 42 kt at liftoff, with an estimated airspeed exceeding 50 kt.
As the aircraft climbed, it was subjected to significant wind fluctuations. At approximately 50 ft, the aircraft exhibited a steep pitch-up followed by a controlled nose lowering, likely as the pilot attempted to maintain airspeed and a proper takeoff profile. However, at roughly 150 ft, a second uncorrected steep pitch-up occurred. This was followed by the nose and left wing dropping, leading the aircraft into an incipient spin. Due to the low altitude, there was insufficient height to recover before the aircraft impacted the terrain.
The investigation
The ATSB examined CCTV footage, witness statements, and the wreckage to reconstruct the event. Investigators noted that while no official weather forecasts were accessed by the pilot, local conditions were characterized by strong, gusting winds, estimated between 10 kt and 30 kt, with a crosswind component of approximately 15 kt.
Analysis of the aircraft's engine sound via CTAF broadcasts and post-accident inspections confirmed that the engine was functioning normally and there was no pre-existing damage to the airframe. The investigation focused on the aerodynamic response of the aircraft to the wind. The evidence suggests that the pilot's control inputs to counteract a right-hand crosswind likely caused the angle of attack on the left wing to exceed the critical limit.
Findings
- The aircraft was flying at an airspeed only slightly above its 48 kt stall speed, leaving a minimal buffer to compensate for sudden wind changes.
- Strong and gusting winds, including significant crosswind components, contributed to an unstable aircraft attitude.
- The aircraft's left wing stalled, leading to an incipient spin.
- The stall occurred at a height of approximately 150 ft, which provided inadequate time for recovery.